The identification of specific allergens in allergenic extracts is of great importance to further understand the mechanism of allergic reactions and to allow proper standardization of commercially available allergenic extracts. We are investigating the human IgE response to specific protein bands by separating the crude extracts using electrophoresis, followed by electroblotting the proteins on to nitrocellulose and immunoclotting with serum from allergic patients. We have found several reactive bands in apple extracts and we have obtained the amino-terminal protein sequence from two specific reactive bands. We are in the process of cloning the genes from an apple cDNA library that code for these specific apple allergens.